Range adapter for mortars



Oct. 19, 1948. B. WALKER RANGE ADAPTER FOR MORTARS 2 Sheets-Sheet 1 Filed Aug. s, 1945 3mm E1 rm mks Walkr Oct. 19, I948. B. WALKER 2,451,524

RANGE ADAPTER FOR MORTARS Filed Aug. 6, 1945 2 Sheets-Sheet 2 F mm W gwue/wtom Elruuks Walker 3% wz wwwmw Patented Oct. 19, 1948 FEED STATS or-rics (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. 'G. 757) 18 Claims.

The invention described herein maybe manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to weapons of the type commonly known as trench mortars.

An object of the invention is to provide a means of obtaining shorter ranges of mortar 'fire than are usually available 'With present ammunition and an les of fire.

Another object :of the invention is to provide means whereby an ordinary trench mortar using ordinar mortar ammunition may without any changes other than by the addition of a removable adapter of simple construction, be fired at much shorter ranges than usual, and greatly reduced muzzle velocities obtained in which the maximum ordinate pertainin to the trajectory of the shell is decreased.

A further object of the invention is to provide an adapter for shortening the range of a mortar, which adapter is quickly and conveniently inserted into and removed from the mortar barrel.

Another object of the invention is to provide an adapter the size of which may be varied to provide desired variations in range of the mortar fire.

Other purposes and advantages of the invention will become apparent from the preferred embodiment of the invention which is described below and illustrated in the accompanying drawings in which:

Figure 1 is a side elevation of a mortar which is partly broken out, showing the adapter and mortar shell inside the mortar barrel,

Figure 2 is a cross-sectional view taken along line 2-2 of Figure 1,

Figure 3 is a longitudinal sectional View of the adapter,

Figure 4 is a perspective view of the adapter and its component parts,

Figure 5 is a plan view, partly broken out, of a modified adjustable form of adapter,

Figure 6 is a cross-sectional view taken along line 6-5 of Figure 5,

Figure 7 is a longitudinal sectional View of a modified form of adapter made of a plurality of tail fin assemblies with a firing pin,

Figure 8 is a cross-sectional view taken along the line-8--8 of Figure '7,

Figure 9 is a longitudinal sectional view of another modified form of adapter, and

Figure 10 is a cross-sectional view taken along line 10-10 of Figure 9.

In the use of weapons of the type commonly known as Stokes mortars or trench mortars, it

has become desirable for them to be fired at short range targets on the order of yards away, more or less, such as firing from a beach or at close enemy positions like trenches, caves, buildings and foxholes.

It is also desirable, whenever possible, -f0r the shorter ranges to 'be obtained without changing the usual mortars and mortar ammunition, thus avoiding the need for extensive specialized field equipment which may not be available when and where required.

This invention is intended .to provide a simple form of adapter which can be placed inside the mortar barrel and which will effectively operate to reduce the range of the shells'fired.

Referring now'to the drawings, Figure 1 illustrates a trench mortar 2 in firing position, the mortar having a tube or barrel 4 with a base cap 6 closing its breech end 8, :the cap 6 having a pro- Jection Hi extending into a matching .recess formed in the upper surface 12 of a base plate M located on the :ground or other suitable surface iii. The mortar has the usual elevating and traversing support mechanism I8 resting on the round or other surface H5 at its lower end 20 and secured at its upper end 22 to the mortar barrel 4 as indicated, whereby the barrelelevation and direction of fire may be adjusted .in the usual manner. The base cap -6 of the mortar may be provided with a short striker or firing .pin v2'4 extending upward from a raised circular platform or propellant cartridge support 25 into the breech end of the barrel bore, and the firing pin may be fixed in position so that it will actuate the percussion primer located in the tail assembly of a mortar shell dropped into the open muzzle end of the mortar barrel. Or the base cap 6 of the mortar may be provided with atrigger mechanism in which the firing pin 2' is normally retracted and wherein a continuous pull on the lanyard 26 will cause the firing pinto be pressed so it projects into the breech end of the barrel bore, striking against and actuating the primer located on the tail assembly of a mortar shell located in the mortar barrel. The lanyard may trip a spring loaded firing pin to fire the mortar shell Dropelling charge.

According to the present invention, the mortar shell 28, instead of being at the bottomor breech end of the barrel bore 30 at the time the propelling charge in the .tail assembly is fired, is instead to be at some location nearer to the muzzle end 32 of the barrel bore. This is accomplished by providing an adapter or support member 34 which serves to elevate the shell28 to the desired position nearer to the muzzle end 32. As illustrated in Figures 3 and 4, the adapte 34 has an elongated cylindrical body portion or support member 36 with radial fins 38 secured to said body 38 in groups of four-at any'eonvenient locations 40 and 42 near each end of the body 35. The-fins 38 are of such a length that when the adapter is in the barrel bore their outer extremenlarged portion 52 located in enlarged bore 48,

As is illustrated in Figure 3, the enlarged bore 48 is longer than enlarged rod portion 52,.the total length of therod 50 including portion 52,

being equal to the length of :body portion 36.

remove the. adapter from the barrel, the barrel may be tilted over, allowing the adapter to fall .out, or a piece of hooked wire may be used to lift the adapter out by catching it under one of the vanes 38.

Where a number of increments of possible short ranges are desired without using-more than one adapter, the modified construction shown in Figures and 6 may be used. This shows a cylindrical member 60 arranged for. telescoping inside a central bore 6! in a hollow cylindrical housing 62. The housing .62 has a number of pairs of transverse aligned holes 64 and the member 60 has at one end atransverse hole 66 which may holes 54 in. the housing 62, .a. removable pin. 68

be aligned with any selected pair of transverse being inserted through the aligned holes 64 and 66 and held in place b a wire clip I0 engaging,

both the pin 68 and the housing 62 as shown. The member 60 has near one end I2 a plurality of radial pins or vanes 14 of a length suitable for is thus to be noted that if enlarged rod portion 52 is pressed into enlarged bore 48 as far as the rod will go, as shown in Figure -3, theresult will be to make the opposite end 54 of the rod 50 proi trude out of theend 56 of body portion'35 as illustrated, thus forming a second firing'pin or striker at 54.

In use, the adapter34 is dropped inside the barrel bore'30 with its end 56 uppermost as shown in Figure l. The other end 58 of the adapter 34 will be located at the bottom of the breech end of the barrelbore 30. If the-mortar uses a fixed firing pin 24 then the firing pin 24 will project upward into the barrel bore and into the enlarged end 48 of central bore 4 .6 ofthe adapter 34. As a result, the firing pin 24 will press therod 50 into the position inside bore 46 as shown in Figure 3, and the'end 54 of therod will protrude from the upper end 56 of the adapter, the protruding end 56 thus becoming a new elevated firing pin for firing a mortar shell 28 dropped into the mortar barrel.

The end 56 of the adapter 34 may, if desired, be slightly enlarged as shown, in order to provide added support for the propellent cartridge primer carrier of the mortar shell. The enlarged end 52 may be provided with a slot 53 through which extends a removable wire 55 supported in matching holes 5'! through member 36, thus preventing rod 50 from dropping wholly out of bore 46.

If the mortar is trigged fired, then the same adapter 34 may be used without an changes. In that case, the firing pin 24 does not project upwards until the trigger lanyard 26 is pulled hence the rod 50 similarly does not protrude at 54 until the trigger is actuated. A mortar shell 28 is dropped into the barrel 30, coming to rest with its tail assembly 38 supported by end 56 of the adapter 34. The lanyard 26 is then pulled, causing the movable firing pin 24 to project into the enlarged bore 48 of the adapter, pushing rod 50 and causing its end 54 to protrude, firing the mortar shell.

The effect of the spacer or adapter 34 is to lessen the maximum possible pressure of propellent gases inside the mortar barrel bore resulting from firing a propellent cartridge and to shorten the projectile travel in the barrel, thus lessening considerably the range. The reduced maximum propelling pressure is accomplished by providing around the solid parts of the adapter 34 an additional gas expansion space for expansion of the propellant gases. The adapter 34 may be made in any length suitable for the range desired. To

' bore 30 in a slidingfit, and for centering the I tension 18 secured tohousing 62 by rivet 80 as just touching the inside surface of mortar barrel adapter in the barrel bore.

Similar radial pins 16 are provided in an exshown. A firing pin 82 protrudes from extension it for firing a mortar shell 24 dropped into a mortar barrel in which the adapter is located with the pin 82 nearest the muzzle end of the bore. The range is adjustable by varying the keeping the contact surfaces H2, H4 and H6 of' length of the adapter as explained.

Figure '2 shows: how an adapter may be made from one or more extra mortar shell tail assem- Thus there are tail assemblies 84, 86, and.

blics. 38, each having radial vanes or fins 90, a threaded extension '92 and a threaded recess 94. The tail.

assemblies may be secured together by threading next-one, using inside and outside threaded bush.- ings 96where the mating parts are notthe same size. The extension 92 of the end assembly 84 has a central recess 38 bored into it and a short rod or firing pin I00 secured into the recess, protruding partly out as shown. In operation, to make an adapter, the requisite number of tail assemblies for the desired length of adapter is threaded together as shown, and the adapter dropped inside the barrel bore 30. The fins are already of a length proper for centering the adapter in the bore 30 and will not bind in the barrel. With the adapter in the barrel, any shell 28 dropped in will be fired by the firing pin I00, at a short range as explained.

Another. modification of the adapter is illustrated in Figure 9. There is a cylindrical body portion I02 having near each end two radial fins I04 and I06 with an angle of degrees between them, and a member I08 made of spring Wire or other suitable material, fastened at one end IIO to body portion 50-2 and forming an arc extending radially outward, the plane of member I08 making an angle of 120 degrees with each fin I04 and I06 as shown. Since the member I08 is a spring member, it bears against the inner surface of the mortar barrel bore 30 at H2, thereby the radially extended portions of the adapter pressed against the inside of the barrel bore 30, preventing the adapter from too easily sliding out of the barrel or rattling during handling and moving thereof. The adapter shown in Figure 9 has a central rod 50 slidably disposed in a central bore 46 with enlarged portions just as in Figures and already described. The adapter is similarly placed in the barrel bore with the end 56 nearest the barrel muzzle.

Although the invention has been described in specific terms, it is to be understood that numerous changes may be made in size, shape, arrange ment and materials without departing from the spirit of the invention and its scope as claimed below.

I claim:

1. In a muzzle loading trench mortar having a Y firing pin disposed in the breech end of the barrel bore thereof for actuating the propellent charge carried on the tail end of a mortar shell, the combination with said pin of an elongated rod constituting a firing pin extension, coaxially disposed in said bore with its rearward end in contact with the forward end of said firing pin and its forward end extending forwardly of said firing pin and constructed and arranged for firing a mortar shell.

2. In a muzzle loading trench mortar having a firing pin disposed in the breech end of the" barrel bore thereof for actuating the propellent charge carried on the tail end of a mortar shell, the combination with said firing pin of a removable firing pin extension receivable in said barrel bore for shortening the mortar range, comprising an elongated member coaxially disposed in said barrel bore with its rearward end in contact with the forward end of said firing pin, means on said member radiating therefrom to the inner barrel bore surface for maintaining said member in coaxial relation with said barrel bore, and a second firing pin projecting forwardly from said member for firing a mortar shell propellent charge.

3. The construction of claim 2 wherein said means radiating from said member comprises a plurality of radial vanes of equal lengths.

4. The construction of claim 2 wherein said means radiating from said member comprises a plurality of vanes formed of sheet metal.

5. In a muzzle loading trench mortar having a firing pin disposed in the breech end of the barrel bore thereof for actuating the propellent charge carried on the tail end of a mortar shell, the combination with said firing pin of a removable firing pin extension receivable in the barrel bore for shortening the mortar range, said extension comprising an elongated cylindrical member coaxially disposed in said barrel bore with its rearward end in contact with the breech end of said barrel bore and having a central longitudinal bore extending therethrough, a plurality of members of relatively thin cross section radiating therefrom to the inner surfaces of said barrel bore for maintaining said cylindrical member coaxially Within said bore, a rod of relatively small cross section and of the same length as said cylindrical member slidably disposed within said central longitudinal bore with its rearward end in contact with the forward end of said firing pin and its forward end forming a second firing pin for firing a propellent charge carried by a mortar shell.

6. The construction of claim 5 wherein said first mentioned firing pin normally projects forwardly inside the rearward end of said central longitudinal bore, thereby causin said second firing pin to normally project forwardly out of the forward end of said longitudinal bore.

7. In a muzzle loading gun, a barrel, a cartridge support and a firing pin disposed in the breech end of said barrel, a firing pin extension and a cartridge support extension disposed in said barrel adjacent to the breech end thereof and coaxial with said firing pin and said cartridge 6 support respectively, and means for maintaining said extensions axially within said barrel.

8. The construction of claim 7 wherein said last named means comprises a plurality of vanes of equal length radiating from said cartridge support extension to the inner surface of said barrel.

9. The construction of claim 7 wherein said last named means comprises a plurality of uniformly spaced members of equal length radiating from said cartridge support extension to the inner surface of said barrel.

10. In a muzzle loading trench mortar comprising a barrel having a bore and carrying a first firing element at its breech end, means for shortening the range by increasing the initial volume of gas expansion space existing between the mortar shell and the breech end of the mortar barrel bore, comprising a second firing element disposed in the barrel bore at a selected location between said'first firin element and the barrel muzzle, and removable cylindrical means of reduced diameter relative to the bore constructed and arranged for supporting said second firing element at said location.

11. For use in a mortar comprising a barrel having a bore, a range reducer adapted to be positioned in said barrel bore between the breech end of said bore and a mortar shell dropped therein, comprising an elongated member disposed in said bore in coaxial relation therewith, a firing pin carried by the forward end of said member, and a plurality of fins of equal length radiating from said member with their distal ends in sliding contact with the inner surface of said barrel bore.

12. In combination with a smooth bore muzzle loading trench mortar having at its breech end a first firing pin, a removable range reducing device comprising an elongated support member of relatively smaller cross-section than said bore axially disposed therein, said support member having a longitudinal bore extending therethrough, a rod of equal length slidabl disposed in said bore with its rearward end in contact with said firing pin, said rod being in such cooperative relationship with said firing pin so that pressure of the firing pin against said rod will cause it to move forward, to thereby protrude from said bore and form a second firing pin for firing mortar shells from said mortar.

13. In a trench mortar of the type wherein a shell is dropped into the barrel muzzle and is normally fired on impact with a firing pin located in the breech end of the barrel bore, means for shortening the range by causing the shell to be fired before reaching the barrel breech end, comprising an elongated support longitudinally disposed in said barrel bore, a plurality of members extending radially outward from said support member with their outer extremities in sliding contact with said barrel bore whereby said support is maintained centrally in said bore, said support having one end in contact with the breech end of said barrel bore, and a firing pin secured to and projecting from the forward end of said support.

14. In combination with a muzzle loading trench mortar havin a block centrally arranged at its breech end and a first firing pin carried by said block for firing a propellent cartridge carried by a mortar projectile dropped into said mortar, adapter means constructed and arranged for reducing the range of said mortar by firing said propellent cartridge at a selected location between said first firing pin and the muzzle of said mortar, comprising a plurality of mortar shell tail assemblies secured together in coaxial relationship, and a second firing pin carried by the forwardmost of said tail assemblies, said adapter means adapted to be placed inside the mortar barrel with its rearward tail assembl in contact with said block and said second firing pin carried on its forward end for firing a mortar shell dropped into said mortar barrel.

15. In a smooth bore muzzle loading gun having an upwardly projecting first firing pin disposed in the breech end of said bore, the combination, with said bore and first firing pin, of a range reducing adapter comprising an elongated support member having an axial bore extending therethrough, said support member being receivable in said bore with its rearward end in contact with the breech end of said bore and engaging said first firing pin in the rearward end of said axial bore, a plurality of spaced vanes radiating from said support member to the walls of said bore for maintaining said support member in sliding coaxial relation with said bore, a firing pin extension of equal length slidably disposed in said axial bore coaxially with said mortar bore with its rearward end in contact with said firing pin, whereby reception of said firing pin in the rearward end of said axial bore operates to cause the forward end of said firing pin extension to protrude forwardly out of said axial bore to thereby form a second firing pin.

16. In a. trench mortar having a barrel, a bore therein, and a first firing pin carried at the breech end thereof, the combination with the barrel and first firing pin, of a range reducing adapter receivable in said barrel and comprising a hollow supporting member coaxial with and of small cross section relative to said barrel bore, centering means radiating from said support member to the walls of said barrel bore, for maintaining said support member and bore coaxial, said first firing pin being receivable within said support member, and a rod extending axially through said hollow support member, one end of said rod forming a second firing pin on the forward end of said support member and the other end being constructed and arranged to engage said first firing pin whereby upon reception of said first firing pin within said support member said second firing pin is caused to protrude forwardly out of said support member.

1'7. For use in a mortar comprising a barrel having a bore and provided with a first firing pin at the breech end of said barrel, a range reducing adapter comprising a slidable support member having an elongated body portion centrally disposed in said barrel bore of said mortar with its rearward end supported by the breech end of said barrel bore adjacent said first firing pin and its forward end reaching to a selected location between the breech and muzzle ends of said bore, and a second firing pin supported on and projecting forwardly from the forward end of said body portion.

18. In a range reducer adapted for insertion into a mortar comprising a barrel having a bore, an elongated member of lesser diameter than the diameter of said bore and slidably disposed in said bore, vane means attached to said member adjacent the ends thereof and engaging the walls of said bore to locate said member axially of bore, and a forwardly projecting firing pin carried by said member at its forward end.

BROOKS WALKER.

REFERENCES CITED FOREIGN PATENTS Country Date Ital Sept. 25, 1937 Number 

